Water-soluble polymeric compositions such as films include a variety of components such as water-soluble polymers (e.g., polyvinyl alcohol (PVOH)), plasticizers, and various other additives. Such compositions are commonly used as packaging materials to simplify dispersing, pouring, dissolving and dosing of a material to be delivered. For example, packets made from water-soluble film are commonly used to package household care compositions, e.g., as a pouch containing a laundry or dish detergent. A consumer can directly add the pouch to a mixing vessel, such as a bucket, sink or washing machine. Advantageously, this provides for accurate dosing while eliminating the need for the consumer to measure the composition. The pouch may also reduce mess that would be associated with dispensing a similar composition from a vessel, such as pouring a liquid laundry detergent from a bottle. The pouch also insulates the composition therein from contact with the user's hands. In sum, soluble polymeric film packets containing pre-measured agents provide for convenience of consumer use in a variety of applications.
It can be difficult to qualitatively detect or quantitatively measure various components of water-soluble polymeric compositions, in particular after formed into a solid material such as a film. Such compositions can be difficult to analyze using analytical tools such as HPLC (high-pressure liquid chromatography) and GPC (gel-permeation chromatography), so the separation and analysis of their components must be accomplished with more labor intensive methods. Complex separation methods such as soxhlet extraction prior to quantitative analysis can be possible; however such a process is time-consuming and impractical, in particular for rapid quality testing at the industrial scale.
There remains a need for improved qualitative and quantitative analytical detection techniques for water-soluble polymer composition components, in particular where it is important for safety or performance reasons to validate that a specific component is qualitatively present and/or quantitatively incorporated at a desired concentration in the composition.